As known, the detergents used in the household, in commercial establishments and in industry, frequently contain large quantities of condensed phosphates, particularly tripolyphosphates. These are provided to sequester the hardness formers of tap water and are responsible to a great extent for increasing the cleaning power of the capillary-active washing substances. The phosphorus content of these agents has been criticized by the public in connection with questions of the protection of the environment. The view is frequently expressed that the phosphates, which arrive in the rivers and lakes after treatment of the sewage, have great influence on the eutrophication of the waters, and is said to lead to an increase of the growth of algae and of oxygen consumption. It has therefore been tried to eliminate phosphate from the washing and cleaning processes or from the agents used for this purpose, or at least to substantially reduce its proportion.
Copending, commonly-assigned U.S. Patent Application Ser. No. 458,306, filed Apr. 5, 1974, now abandoned in favor of continuation Application Ser. No. 800,308, filed May 25, 1977, and its continuation-in-part application Ser. No. 599,012, filed July 24, 1975 now abandoned, discloses a process for the washing, bleaching or cleaning of solid materials, particularly textiles, by treating these materials with a liquor containing compounds able to bind the cations that make water hard. The process is characterized in that finely-dispersed, water-insoluble silicate compounds having calcium-binding capacity of at least 50 mg CaO/gm of anhydrous active substance (AS) and having the formula I, combined water not shown EQU (M.sub.2/n O).sub.x .Me.sub. 2 O.sub.3 .(SiO.sub. 2).sub.y (I)
where M is a cation of the valence n, exchangeable with calcium, x is a number from 0.7 to 1.5, Me is aluminum or boron, and y is a number from 0.8 to 6, preferably from 1.3 to 4, are suspended in the aqueous treatment bath. The process of the patent makes possible the complete or partial replacement of phosphates that bind calcium ions by complexing and are still being used in the washing and cleaning process.
The calcium-binding capacity of the above-defined compounds may reach values of 200 mg CaO/gm AS and is preferably in the range of 100 to 200 mg CaO/gm AS. The above-defined compounds capable of binding calcium are referred to as "aluminosilicates" in the following text, for the sake of simplicity. This applies particularly to the sodium aluminosilicates that are to be used preferably. All data given for their preparation and processing apply accordingly to the totality of the above aluminosilicate compounds as defined in said earlier application.
The cation M employed is preferably sodium. However, the same can also be totally or partially replaced by other cations exchangeable with calcium, such as hydrogen, lithium, potassium, ammonium or magnesium, as well as by the cations of water-soluble organic bases, for example, by those of primary, secondary or tertiary alkylamines or alkylolamines with not more than 2 carbon atoms per alkyl radical, or not more than 3 carbon atoms per alkylol radical.
This process is indicated as being further improved in that the removal of soil is considerably improved when another compound is employed in the liquor which has a sequestering and/or precipitating effect on the calcium which is contained in the water as a hardening substance. Disclosed as suitable as sequestering agents for calcium were also substances with such a low sequestering power that they were not considered heretofore as sequestering agents for calcium. However, these compounds frequently have the capacity of delaying the precipitation of calcium carbonate from aqueous solutions.
Preferably, amounts of sequestering or precipitating agents of, for example, 0.05 to 2 gm/l, were added to accelerate or improve the removal of dirt. Preferred are amounts of 0.1 to 1 gm/l. Substantially larger amounts can also be used, but if phosphorus-containing sequestering or precipitating agents were used, their amount had to be so selected that the phosphorus load of the sewage was much less than with the presently used triphosphate-based detergents.
Copending, commonly-assigned U.S. patent application Ser. No. 458,326, filed Apr. 5, 1974, now abandoned, and its continuation Ser. No. 723,728, filed Sept. 16, 1976, now U.S. Pat. No. 4,083,793 disclose an improvement in the above invention, consisting of the presence, in the aqueous liquor together with said aluminosilicates of from 1 part by weight of nonionic surface-active compounds and from 0 to 3 parts by weight of anionic surface-active compounds, as said surface-active compound, said nonionic surface-active compounds being a mixture of a compound having a labile hydrogen and from 8 to 18 carbon atoms ethoxylated with from 8 to 20 ethylene oxide units and a compound having a labile hydrogen and from 8 to 18 carbon atoms ethoxylated with from 2 to 6 ethylene oxide units in a weight ratio of 1:0.2 to 2. An improved soil removal, particularly in the case of fatty and oily soils, is achieved by the combination of the aluminosilicates with the above-described tenside component.